Varilux Fitting Guide

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Varilux Fitting Guide

  1. 1. ®VARILUXFITTINGGUIDEA GUIDE TO THE SUCCESSFULFITTING OF VARILUX® LENSES
  2. 2. WELCOMEWe are pleased to present this guide which outlines the essential rulesfor the successful fitting of progressive lenses to your presbyopic patients.Overall, it guides you through successful fitting from first contact to the final deliveryof the spectacles.A genuine working tool, this guide will be found useful in your daily routine and will helpyou to be successful in fitting progressive lenses and help to guarantee patientsatisfaction.Please use it regularly! 2
  3. 3. FITTING VARILUX STEP BY STEP 7 9 17 19 23 25 27 P. P. P. P. P. P. P. T ON S EN PT I NT TI RI E PA M ES E SC RE N TH RE N U NS AT IO NG E P IO EA S LE PT DI TH ECT M THE NG DA TA N NG EL HE G TI A RS ZI E S G T TI N FIT G S IN EM E LY M IN UN AL LV LUND ANA FR A TA K M O FIN SO ROB1 2 3 4 5 6 7 P 3
  4. 4. 1 UNDERSTANDING THE PATIENT This first step is essential to the success of lens fitting 1 What was the patient wearing before?Type of lenses worn Analyzing the previous lenses 2 What are the visual needs?I Single Vision for Distance, Single Vision I Measure the previous correction: What are the spectacles used for? for Near, Mid-distance, Bifocal, sphere, cylinder, axis, addition and Progressive (brand and type)… prismatic correction if any. I Permanent or occasional wear?I Material, colour, coatings… I Date when given the previous lenses I Working distances? I Visual performance with former lenses: Specific requirements? measure acuity for distance and near I Profession, hobbies, leisure. vision. I Clarity of vision necessary. Understand the reasons for any lens I Field of vision needed. change and confirm its need. DÉCOUVRIR LE CONSOMMATEUR 4
  5. 5. 2 ANALYZING THE PRESCRIPTION An overview of the refraction techniques 1 Compare the new correction 2 Compare the value of with the previous one the addition with the onesIf the difference is equal to suggested in the table Age Addition(or more than) … These typical values should only be 40 years 0.75 D exceeded in cases of real necessity.I 0.75 D on the sphere 44 years 1.00 DI 0.50 D on the cylinder 47 years 1.25 D 49 years 1.50 DI 10° on the axis 51 years 1.75 DI 0.75 D on the addition 54 years 2.00 D... confirm its necessity with prescriber 58 years 2.25 Dand ensure its acceptance. 63 years 2.50 D 67 years 2.75 D 70 years 3.00 D 75 years 3.25 D* 80 years 3.50 D* * Additions 3.25 and 3.50 are rarely ever necessary. 5
  6. 6. CHECKING WHETHER THE ADDITION IS TOO STRONG Too strong an addition is often the reason for adaptation problems with progressive lenses 1 Checking near vision correction Using the Essilor “CheckTest” The subject wearing the near vision With an additional power of -1.00 D correction, places the CheckTest at the usual reading distance. Place the -1.00 D lenses in front of the near vision correction of the subject: if the • With the Helmoltz test pattern smallest characters can still be read, even If the circles in the centre of the pattern if with some difficulty, the addition is are seen without deformation, the near probably too strong. vision correction is correct for the reading distance. If the circles are seen deformed, the near vision correction is either correct or too weak. The CheckTest is available for free from • With the red-green test Varilux University. Don’t hesitate to ask If the letters are seen more clearly on for it while visiting our web site at: the green background, the near vision www.varilux-university.org correction is either correct or two weak. If they are seen more clearly on the red background, the near vision correction Image of pattern’s centre is probably too strong.6
  7. 7. CHECKING WHETHER THE ADDITION IS TOO STRONG Too strong an addition often results from an under-correction of distance vision 2 Detecting under-corrected hypermetropiaThis is often the cause of too strong anaddition because it relates directly to thevalue of the addition.With the red-green test in distance With an additional power of + 0.50 Dvision Place the + 0.50 D lenses in front of theIf the subject has a clear preference distance vision correction of the subjectfor reading on the green background and and ask the subject to look in the distance:the letters appear blurred on the red if vision remains clear, or is improved,background, the hyperopia is probably the hyperopia is probably under-under-corrected. corrected.NB. Any prescription changes must be undertaken by a registered prescriber. 7
  8. 8. CORRECTION OF DISTANCE VISION An accurate distance prescription results in the most comfortable near prescription Deal with each eye separately starting 2 Determination of the cylinder b) Verify the cylinder powerS U P P L E M E N T from a trial correction (old prescription or I Place the minus axis of the cross results from an autorefractor). Using the cross cylinder method (± 0.25 D) cylinder along the direction of the 1 Determination of the sphere a) Verify the cylinder axis: correcting minus cylinder. I Position the handle of the cross cylinder I With the subject looking at a line of small Using the fogging method along the cylinder axis direction of the letters, rapidly twirl the cross cylinder 1) Place the trial prescription before trial prescription (it should produce a and ask the subject which position of the the subject’s eye and measure the drop in acuity). cross cylinder is preferred. visual acuity. I With the subject looking at medium size I If the subject prefers the position when 2) Fog the eye by adding +1.00 D letters, rapidly twirl the cross cylinder the minus axis of the cross cylinder lies or +1.50 D to cause a drop in visual and ask the subject which position of the along the axis of the correcting minus acuity. cross cylinder is preferred. cylinder, add -0.25 D to the correcting 3) Unfog progressively by -0.25 D steps I Turn the axis of the correcting minus cylinder. and check that the visual acuity cylinder by 5° towards the minus axis I Repeat this process until the subject improves. of the preferred cross cylinder. cannot (or can hardly) tell the difference. 4) Continue until the best acuity is I Repeat this process until the subject I Record the minimum value of the obtained. cannot (or can hardly) tell the difference. cylinder power found. 5) Record the power of the strongest plus sphere that provides maximum acuity. c) Check the sphere power I Add +0.25 D to the sphere for each -0.50 D added to the cylinder and check that the best visual acuity is still obtained. 8
  9. 9. CORRECTION OF DISTANCE VISION An accurate distance prescription results in the most comfortable near prescription 3 Binocular balance 4) Binocularly, unfog the eyes in -0.25 D I For the cylinder S U P P L E M E N T steps until the maximum acuity is obtained. • Correct the astigmatism only if it resultsIn distance vision, by dissociating the eyes in a noticeable gain in visual acuity.and checking the visual acuity. 5) Check the acuity of each eye, making • Be wary of weak astigmatism, it often sure that ocular dominance has not been1) Dissociate the subject’s eyes varies. reversed between the eyes.• by alternate occlusion: rapidly occlude • Moderate prescriptions with oblique one eye, then the other, with an occluder Some rules axes that may give rise to distortion. or and recommendations I Binocular vision• with vertical prism: introduce 3∆ base I For the sphere • Carefully check binocular balance. down before one eye and 3∆ base up • Always fully correct the ametropia, • Give priority to the dominant eye: do before the other or particularly any hypermetropia, but do not reverse ocular dominance between• by polarization: use a polarization not overplus. the eyes. test for visual acuity together with the • Do not over-correct, rather prefer a slight • In cases of anisometropia, give the mini- corresponding polarizing filters. under-correction. In the red-green test: mum possible difference between the – for hyperopia, “equalize” the red and the2) Fog both eyes with +0.50 D spheres right and left eyes. green or leave “slightly clearer on the and confirm that there is a drop in acuity. green”. I As a general rule3) Balance vision in the right and left – for myopia, “equalize” the red and the • Avoid large changes in prescription: do eyes by refogging the eye with the green or leave “slightly clearer on the red”. not exceed 0.75 D on the sphere, 0.50 D better acuity with a +0.25 D sphere. • Remember that refraction has not been on the cylinder or 10° on the axis, unless undertaken for infinity: add -0.25 D to it is really necessary. the sphere if necessary. 9
  10. 10. DETERMINATION OF THE ADDITION THE “FIXED CROSS CYLINDER” METHOD A reference method for determination of the addition Using the refractor with both eyes open.S U P P L E M E N T 1 Fully correct distance vision 2 Determination of 3 Verify that the subject Use the highest plus sphere which the addition can read comfortably provides maximum visual acuity I Ask the subject to fixate a cross made I Put up the distance correction with the (see previous pages on “Correction of up of vertical and horizontal lines at a proposed near addition in a trial frame. Distance Vision”). distance of 40cm (16 in). I Ask the subject to confirm that vision is I Position ±0.50 D cross cylinders with comfortable when reading. their minus axes at 90° before both I Adjust the value of the addition for the eyes: the subject should report that the subject’s normal working or reading horizontal lines are clearer. distance. I Progressively, place +0.25, +0.50, +0.75 D…lenses before the eyes until the vertical and horizontal lines appear equally black. I The addition is the value which gives the best equality between the horizontal and the vertical lines. 10
  11. 11. DETERMINATION OF THE ADDITION THE “ACCOMMODATIVE RESERVE” METHOD A classic method for determination of the addition 1 Measure the amplitude 2 Determination of 3 Verify that the subject S U P P L E M E N T of accommodation the addition can read comfortablyUsing binocular vision with the distance correc- Normally, subjects should be allowed to use I Put up the distance correction with thetion in place and the use of a near vision chart. two-thirds of their total amplitude of accom- proposed near addition in a trial frame. modation at their usual working distance I Ask the subject to confirm that vision isI With moveable near vision chart: (leaving one-third of their total amplitude in comfortable when reading.Bring the near vision chart in towards the subject reserve) so as to be comfortable. I Adjust the value of the addition for theuntil it is only just legible, the amplitude of The addition is calculated from: subject’s normal working or readingaccommodation is the reciprocal of this distance. Addition = 1 / near distance - 2 / 3 total amplitude. distance. For example: nearest reading distance = 0.50 m, amplitude of accommodation = 2.00 D. Total Usable Addition amplitude of amplitude of for 40 cmI With fixed near vision chart: accommodation accommodation (16 in)• Position the near chart at 40 cm (16 in) 3.00 2.00 0.50 and ask the subject to read. 2.75 1.75 0.75• If can read the smallest text, add 2.50 1.50 1.00 -0.25 D, -0.50 D etc..., binocularly, until 2.25 1.50 1.25 2.00 1.25 1.50 reading is no longer possible. 1.75 1.00 1.50• If cannot read the smallest text put up +0.25 1.50 1.00 1.50 D, +0.50 D etc…, binocularly, until the 1.25 0.75 1.75 smallest text can just be read. 1.00 0.50 2.00 0.75 0.50 2.25 The amplitude of accommodation = 2.50 - final value which has been added. 0.50 0.25 2.50 11
  12. 12. DETERMINING THE ADDITION THE “MINIMUM ADDITION” METHOD A simple and proven method of determining the addition 4 StagesS U P P L E M E N T 1 Good correction 3 Add + 0.75 D to + 1.00 D of distance vision to the minimum addition to find the I Fully correct the ametropia, in particular comfortable addition value. any hyperopia. I Do not over-correct. 4 Checking the patient’s With the red-green test: visual comfort • for the hyperope, keep “equal” or I Have the patient evaluate whether reading “sharper on the green”, is comfortable with the addition found. • for the myope, keep “equal” or “sharper I Ask the subject to bring the text closer on the red”. until the reading of small characters is I Correct astigmatism only when it impossible: it should occur at approxima- provides a real gain in visual acuity. tely 25 cm / 10 in from the eyes. If it 2 Determining the minimum occurs closer than 20 cm / 8 in, the addi- tion is too strong, if it occurs further than addition at 40 cm (16 in) 30 cm / 13 in, the addition is too low. Add binocularly + 0.25 D, + 0.50 D, etc… I Adjust the value of the addition by 0.25 D to the distance correction until the patient just according to the usual working or reading distinguishes the smallest characters: distance. the value found is the minimum addition. 12
  13. 13. 3 FRAME SELECTION The correct choice of frame is important for overall comfort 1 Selecting the frame 2 Adjusting the frameSelect a frame which is right for the Adjust the frame to fit the face of the clientwearer’s face, that is stable on the nose so that:and offers sufficient height between the I The vertex distance is approximatelypupil and the lower rim of the frame. 12 to 14 mm. I The pantoscopic angle is in the region 17 mm minimum for Varilux Physio.18 mm minimum for Varilux Panamic and Varilux Comfort. of 8° to 12°. Proceed with the adjustments in the order: I Adjustment of the front of the frame: projection, inclination, horizontality. I Adjustment of the sides of the frame: opening, shape and length, ear pieces, 18, 16 or 14 mm for Varilux Ipseo. closure of the sides. 14 mm minimum for Varilux Ellipse. The frame should always be adjusted before starting to take measurements. 13
  14. 14. 4 TAKING THE MEASUREMENTS A crucial step for the success of lens fitting Measure then check2 Stages 1 Taking the measurementsMeasuring the pupillary distance I Measure each eye separatelyI Use the CRP (“Corneal Reflection with both eyes open. Pupillometer”) ensuring that the nose pieces have been adjusted so that they rest in the same position as the bridge I If the wearer sees 2 images, measure of the final frame and checking that it is one eye at a time, using the eye mask in contact with the forehead. of the pupillometer. I Measure the monocular pupillary dis- tances, right and left, in distance vision (infinity) and, in near vision (at 40 cm / 16 in) if needed. 14
  15. 15. 4 TAKING THE MEASUREMENTS A crucial step for the success of lens fitting Measure then check Measurement of the pupillary heights I Use the HMS (“Height Measuring System”) in order to obtain the Boxing measurements of pupillary heights for the right and left eyes. I Adjust the frame on the face of the I Adjust the right and left cursors to I Read the right and left pupillary heights patient and set the HMS taking care not the height of the pupil centres placing in the Boxing system: make sure that to modify the position of the frame. yourself at the same level as the eyes the measurement is taken to the lower I Preferably in a standing position, ask of the patient to avoid any parallax error horizontal tangent to the lens (inside the client to adopt a natural position (it can produce an error of several mm). groove of rimmed frame). and to look into the distance at eye level. For accuracy take the measurements with the subject standing up and looking into the distance.15
  16. 16. 4 TAKING THE MEASUREMENTS A crucial step for the success of lens fitting Measure then check 2 Checking the measurements Checking in near vision (optional)I Using the Ditest or the centring I Using the VP System, check using the chart mark the fitting cross position mirror method the correct positioning at monocular PD and height of the eyes in near vision: corneal measurements, for each lens, reflections should coincide with the as well as the position of the near near vision circles. vision circle. Reposition the frame I If there is a manifest asymmetry take it on the wearer’s face. into account by shifting each near vision PD by the required value while keeping With the Ditest, select the diameter of the the binocular PD measured at 40 cm / lenses needed or determine precisely the 16 in with the pupillometer at 40 cm / pre-calibration measurements (in the 16 in. To obtain the distance centration Boxing system) by measuring them on the add 2.5 mm to the near vision PDs frame. The order for Varilux lenses is now found. ready be placed.Checking distance centrationI In a standing position ask the patient to look into the distance, position yourself in front at eye level and check that the centring cross lies in front of the centre of each pupil (see photo below). 16
  17. 17. 5 MOUNTING THE LENSES Points to keep in mind 1 Check the conformity I Prism verification is carried out by placing the focimeter at the prism of the lenses control point. The prism measured is and of their markings the resultant of the thinning prismI Verification of the distance prescription: (the value of which is equal to 2/3 of the measurement is carried out placing the addition) and of any prismatic the concave side of the lens in contact correction prescribed. with the support cone of the focimeter. The control circle for distance vision I Verification of the addition: it is the must be centred on the aperture of the difference between the power for near focimeter, the axis of the lens being vision and the power for distance vision horizontal. measured on the front side. It is also possible to read its value directly fromI Verification of the near prescription: the 2 digits engraved under the the measurement is carried out by temporal micro-circle. placing the convex side of the lens in contact with the support cone of the I Verification of markings in order to focimeter. check their correct position compared 34 The near vision circle must be centred with the engravings (see scheme on the aperture of the focimeter. herein). 2,5 17
  18. 18. 5 MOUNTING THE LENSES Points to keep in mind 2 Make sure that both centring 3 Check the conformity 4 Make sure the frame and mounting are made of the mounting is correctly set up in the Boxing system Using the Ditest device or the centring Pre-adjust the frame paying particular I All values must be given in the Boxing chart, check: attention: system. I the right and left PDs, I to the positioning of the lenses in I Centring and edging equipment must I the right and left heights, the same plane, function in this system. I the horizontality of the mounting: I to the pantoscopic angle. by the alignment of the micro-circles. 5 Retain the lens markings until delivery (or retrace them if they have disappeared)18
  19. 19. 6 FINAL FITTING The moment of truth 1 Adjust the frame 4 Check the vision quality 6 Inform the client about to the patient’s face I In distance vision using a visual the learning period acuity test, necessary for each new 2 Check centring using pair of lenses I In near vision using a reading test. markingsI In distance vision (general case): fitting 5 Give recommendations cross in correspondance with pupil to assist adaptation centre for the right and left eyes. I Distance vision at eye level,I In near vision (specific case of looking straight ahead. convergence asymmetry): in the client I Near vision in the lower part of reading position, corneal reflex should the lens, by lowering the eyes be seen through the near vision circle. (and slightly raising the head if 3 Finalise the frame necessary). I To begin, all head and eye adjustment movement should be carried out slowly. 19
  20. 20. 7 SOLVING ADAPTATION PROBLEMS It is necessary to follow a precise sequence in order to determine the problem Thorough research must be conductedGeneral steps 1 Record the precise 3 Remark the lenses 5 Check the adjustment complaints of the wearer of the frame I Fitting cross for distance vision andI Type of problem encountered, frequency near vision circles. I Vertical and horizontal alignment, and particular circumstances of problem, pantoscopic tilt and stability. distances concerned, expedient solutions 4 Check the correct centration 6 Validate the subject’s found, etc… of the lenses prescription 2 Measure the lenses I In distance vision and in near vision, I Measure the acuity at distance frame positioned on the wearer’s face.I Power of distance vision, near vision and at near. and addition. I Confirm the value of the addition as related to the age. 20
  21. 21. 7 A TABLE OF CAUSES TO EXPLORE This table relates to the complaints most often presented by wearers with characteristics which were eventually blamed. CHARACTERISTICS EVENTUALLY BLAMED V V me eN eD e fra n anc tanc ight s/ey f the s tio dist dis g he n en t len n o ens tism e ec efl illary illary ntin visio ition stm ance inatio er l gma WEARERS COMPLAINTS ti-r up p u r d ju t l rm sti POSSIBLE SOLUTIONS An P Pu Mo Fa Ad Ad Dis Inc Fo A Has to raise head or lift lenses to read I Modify the adjustment by lifting the frame I Increase the distance or near powers I Mount new lenses higher up Needs to lower lenses or head to see better in dis- I Modify the adjustment by lowering the frame tance vision I Reduce the distance or near powers I Mount new lenses lower I Modify the adjustment Needs to tilt head to see clearly I Modify the centring I Check the astigmatism I Reduce the addition Has a very reduced near vision field. I Reduce the addition and increase the distance power Fatigue after prolonged work in near vision I Check the astigmatism I Modify the centring: mount lenses higher I Verify the balance between right and left lenses I Reduce the distance power Sees out of focus in lateral vision I Reduce the addition I Check the distance PDs and modify the centring I Check the pantoscopic angle I Check the adjustment and the pantoscopic angle21
  22. 22. 7 A TABLE OF CAUSES TO EXPLOREThis table relates to the complaints most often presented by wearers with characteristics which were eventually blamed. CHARACTERISTICS EVENTUALLY BLAMED V V me eN eD e fra n anc tanc ight s/ey f the s tio dist dis g he n en t len n o ens tism e ec efl illary illary ntin visio ition stm ance inatio er l gma WEARERS COMPLAINTS ti-r up p u r d ju t l rm sti POSSIBLE SOLUTIONS An P Pu Mo Fa Ad Ad Dis Inc Fo A I Check distance and near pupillary distances and heights to confirm centringSees double at distance or near or both I Check distance and near powers, astigmatism and balance between right and left eyes. I Check the adjustment and pantoscopic angle I Compare with the previous spectaclesSees light sources doubled I Make new lenses with an anti-reflective coating I Verify the astigmatism I Check the astigmatism I Reduce the additionSees lines deformed I Check the distance and near PDs and the heights to check centring I Modify the adjustment by lifting the frame or mount the new lenses higher I Check the distance and near PDs and the heights to check centringHas burning, itching sensation, I Check distance and near powers, astigmatism andfeels ocular fatigue balance between right and left eyes I Compare with the previous spectacles I Make new lenses with an anti-reflective coating 22
  23. 23. For further informationor for downloading this Varilux Fitting Guide visit our web site at: www.varilux-university.org
  24. 24. www.varilux-university.org Optics keeps progressing. So will you. © Copyright Essilor International – All rights reserved – Varilux® is a trademark of Essilor International – Produced by Varilux University – English v2 – 01/06

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